Detached ADUs
A standalone backyard home with its own kitchen, bath and entrance. A good fit for rental income or family.
Licensed General Contractor · Since 2001
ADU Contractor in Los Angeles & the Inland Empire
K-Mag Development builds backyard homes, garage conversions and additions, from permits to final inspection. Over 25 years of honest, quality work for Southern California families.
25+Years in business
000+Projects completed
Licensed& insured in California
FreeWritten estimates
What we build
ADU Construction Services
An ADU (accessory dwelling unit) adds living space and value to your property. Use it for rental income, a home for your parents or grown kids, or a quiet place to work.
Garage Conversions
Turn an unused garage into a comfortable, permitted living space. Often the fastest and most affordable ADU.
Attached ADUs
A full living unit connected to your home, with a private entrance, kitchen and bathroom.
Junior ADUs (JADU)
Convert space inside your house, up to 500 sq ft, into an independent unit with its own entrance.
Plans & Permits
We coordinate the drawings, engineering and city permits, so you don't have to deal with the paperwork.
Additions & Remodels
Room additions, kitchens, bathrooms and whole-home remodels, built by the same trusted team.
Why K-Mag
What Makes Us Different
25 Years of Experience
We've been building in Southern California since 2001. We know the work, and we know local codes.
We Handle the Permits
Plans, engineering and city approvals are coordinated for you, start to finish.
Clear Written Pricing
A detailed estimate up front, so you know what you're paying for. No surprises.
Licensed & Insured
A California-licensed general contractor with a clean, respectful crew on every job.
Our work
Featured Projects
Before & After: Garage Conversion
From storage space to a full living unit with a kitchen and bathroom.
Simple and clear
How We Build Your ADU
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1
Free Consultation
We visit your property, listen to your goals and talk honestly about budget and options.
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2
Design & Permits
We prepare the plans and handle the city approval process from start to finish.
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3
Construction
Our crew builds it right, keeps the job site clean and keeps you updated along the way.
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4
Final Inspection
We walk through every detail with you and the inspector, then hand you the keys.
A message from the owner
A Builder You Can Trust Since 2001
K-Mag Development, Inc. is led by Ruben Cendejas and has been building homes, additions and remodels across Southern California for more than 25 years.
[A few sentences from Ruben in his own words: why he started K-Mag, how he treats every home like his own, and what customers can count on.]
Testimonials
What Our Customers Say
[Customer review: what we built, their city, and how it turned out.]
[Customer review: what we built, their city, and how it turned out.]
[Customer review: what we built, their city, and how it turned out.]
Where we work
Serving Los Angeles County & the Inland Empire
Los Angeles County
- Los Angeles
- Pasadena
- Pomona
- Diamond Bar
- Walnut
- West Covina
- Covina
- Claremont
- La Verne
- San Dimas
- Whittier
- El Monte
Inland Empire
- Chino Hills
- Chino
- Ontario
- Rancho Cucamonga
- Upland
- Montclair
- Fontana
- Eastvale
- Corona
- Riverside
- Jurupa Valley
- Norco
Don't see your city? Give us a call. We likely serve your area.
Common questions
ADU Questions, Answered
How much does it cost to build an ADU in Los Angeles?
Cost depends on the type and size of the ADU, your lot, and city requirements. Garage conversions are usually the most affordable option, and new detached ADUs cost the most. We give free, detailed written estimates after visiting your property.
How long does it take to build an ADU?
Most projects take several months from first meeting to move-in. City plan review is often the longest step and varies by city. We give you a realistic schedule up front and keep you updated.
Do I need a permit to build an ADU in California?
Yes. California law allows ADUs on most residential lots, but every ADU must be permitted by your city or county. We coordinate the plans, engineering and permits for you.
Can I rent out my ADU?
In most cases, yes. Many homeowners build an ADU for long-term rental income. Some cities restrict short-term rentals, so we will go over your city's rules with you.
What areas do you serve?
We build throughout Los Angeles County and the Inland Empire, including Chino Hills, Chino, Ontario, Pomona, Rancho Cucamonga, Riverside, Corona and the San Gabriel Valley.
Free estimate
Let's Talk About Your Project
Tell us a little about what you have in mind and we'll get back to you within one business day. Prefer to talk? Call or text anytime.